Unit heater



March 6, 1934. J. Y. DAHLSTRAND UNIT HEATER Filed Jan. 13, 1935 ATTORNEY Patented Mare 6, 1934 PATENT OFFICE UNIT HEATER Josef Y. Dahlstrand, Burlington, Iowa, assignor to Murray Iron Works Company, Burlington, Iowa, a corporation of Iowa Application January'13, 1933, Serial No. 651,516

5 Claims.

This invention relates to unit heaters of the type embodying a heating coil and a fan or the like for circulating air over and through the coil and into the space to be heated.

Heaters of the kind to which this invention pertains are often used in warehouses where perishable goods such as foodstuffs are stored and where it is essential that a uniform temperature be maintained. Heaters operated by electric motors are subject to the disadvantage that, in the event of failure of the electric current, the heater is rendered inoperative and hence the temperature is not maintained and this may result in a waste of the products in the warehouse. However, by utilizing the source of heat to operate a turbine, the likelihood of the failure in operation will not result unless there is a complete failure in the source of heat in which case it is immaterial whether or not the fans are operated.

Hence the objects of the present invention are to provide a novel unit heater which may be operated by a source of heat such as steam so that, so long as heat is supplied, the device will continue to operate; to provide a unit heater having a fan operated by a steam turbine and to exhaust the steam from the turbine into the coil so that heat may be extracted therefrom by the'air moved by the fan and wherein a part of the steam may be passed directly into the coil without first passing through the turbine; and to provide a heater of simple and economical construction and eificient and positive operation.

A selected embodiment of the invention is illustrated in the accompanying drawing andreferring thereto Fig. 1 is a longitudinal vertical sectional view.

Fig. 2 is a transverse sectional view taken substantially on the line 2 2 of Fig. 1.

Fig. 3 is a detail view partly in section showing the turbine.

Fig. 4 is a horizontal sectional view taken substantially on the line 44 of Fig. 3, and

Fig. 5 is a fragmentary detail view taken substantially on the line 5-5 of Fig. 4.

In the accompanying drawing 6 indicates the housing of the heater which may be either supported from an overhead structure or which may be supported on suitable legs 7. The bottom of the housing is open to permit the free entrance of air and mounted in the housing adjacent the bottom and on opposite Walls thereof are headers 8 and 9. A plurality of tubes 10 extend between the headers 8 and 9 and fins 11 are provided on ing coil and air passed therethrough absorbs heat from a heating medium circulating through the tubes and headers. A fitting 12 is mounted in the wall adjacent the header 8 and includes an elbow 13 leading to the header 8 and providing an inlet. Another elbow 14 extends from the fitting 12 and provides an exhaust for the turbine 15. The turbine includes a flange 16 which is bolted to the adjacent wall of the housing 6 and rigidly supports the turbine in position. A steam inlet pipe 17 leads from the thermostatic valve 18 to which the steam supply pipe 19 is connected. Steam flowing from the pipe 19 through the valve 18 and inlet pipe 17 passes into a steam chest 20 in the casing 15 of the turbine. A nozzle 21 extends through the turbine casing from the steam chest 20. The mouth of the nozzle is arranged adjacent the buckets 22 provided on the periphery of the wheel 23 fast on the shaft 24 of the turbine. The nozzle 21 is preferably of the kind described and claimed in my Patent No. 1,561,835, patented November 17, 1925 and, as described therein, is a straight reamed hole. To provide for efiicient expansion of the steam in the nozzle, a tapered needle valve 25 is extended into the throat of the nozzle. The needle valve 25 includes a threaded stem 26 mounted in a block 27 secured in a tapped opening in the wall of the steam chest 20. This permits adjustment of the needle valve 25 relative to the intake of the nozzle 21 so that the nozzle area may be varied and to provide for proper expansion ratio for'the steam pressure and other-operating conditions.

A by-pass 28 extends between the steam chest 20 and the chamber in the casing 15 in which the wheel 23 is mounted. A valve 29 is mounted on a threaded stem 30 which extends through a tapered block 31 mounted in the wall of the steam chest 20. By adjusting the position of the stem 30 and the block 31, the position of the valve 29 relative to the mouth of the by-pass 28 may be varied so as to afford regulation of the quantity of steam passing through the by-pass 28. The steam flowing into the chamber in the casing 15 through the by-pass 28 does not interfere with the operation of the wheel 23 because ample clearance is provided about the wheel. The exhaust port 32 of the turbine is connected to the elbow 14. The

nozzle 21 directs the jetting steam-against the buckets 22 on the wheel 23 and the kinetic energy of the steam is converted into mechanical work since the expansion of the steam induces rotation of the wheel. In order to increase the efficiency of the device, a reversing chamber 33 is provided and steam flowing from the blades 22 across the housing 6 and the end thereof opposite that connected to the turbine is journaled in the bearing 34. In the present instance, three openings are provided in the top wall of the housing 6 and three fan housings depend into the housing 6 from these openings. Openings 36 (-Fig. 1).

are provided in the side walls of the fan housings 35. The blower fans 38 in the fan housings are fast on the shaft 24. Thus when the shaft 24 is rotated by the turbine, the blower fans 38 draw air through the open lower end of the housing 6 through the heating coil and openings 36 and exhaust the air through ducts 39 mounted over the openings in the top wall of the housing 6.

I may provide a valve 13 in the elbow 13 to permit steam to escape into the'air to be circulated by the fans for the purpose of humidifying the The thermostatic valve 19 may be controlled by the temperature of the room into which the air is exhausted and, as the temperature rises, the valve acts to cut down the quantity of steam supplied which not only reduces the quantity of steam flowing to the heating coil but also slows down the blower fans proportionately and therefore a sensitive control is provided.

It may be desirable to use the device for air circulating purposes when no heating is desired and to this end a bracket 40 may be secured to the housing 6 adjacent the bearing 34 and an electric motor 41 may be mounted on this bracket and coupled to the shaft 24. Operation of the motor rotates the shaft 24 and operates the blower fans and air is therefore drawn from the open lower end of the housing 6 and exhausted through the ducts 39.

By carefully calculating the nozzle area, bucket design and the like, it is possible to provide -a turbine which will be operated by the steam pressures commonly used for heating purposes only, say for example, pressures of fifteen pounds or less. The utilization of such pressures is enhanced by providing the reversing chamber which increases the efficiency of theturbine. Furthermore, the turbine may be designed so as to either discharge at atmospheric pressure or at two or.

three inches of vacuum. The device is compact in design and economical in operation. Since theoperating parts are driven by the heating medium, it is clear that so longas the heating me-' lected embodiment herein shown and described It is to be but desire to avail myself of any changes, alterations and rearrangement of parts as may fairly fall within the scope of the following claims:

I claim:

1. In a unit heater. the combination of a steam turbine, means to by-pass steam around said turbine, a coil heated by steam exhausted from the turbine and from said means and passed through said coil, a fan operated by the turbine to circulate air heated by said coil, and thermostatic meansfor regulating the speed of the fan and the heat of the coil.

2. In a unit heater, the combination of a steam turbine including a casing having a turbine wheel therein and an outlet from said casing, means to by-pass steam through said casing past said wheel to said outlet, means directing steam against said wheel to motivate the same,the steam motivating said wheel flowing therefrom to said outlet, heating means in said heater and conneeted to the outlet ofsaid turbine whereby steam flowing from said outlet passes through said heating means, and air moving means operated by said turbine and circulating air through said heating means to heat said air, said air moving means also expelling the heated air from said unit heater.

3. In a unit heater, the combination of a steam turbine embodying a casing including a steam chest and an'outlet, a wheel mounted in said casing and having buckets thereon, a nozzle leading from said steam chest and directing steam against said nozzles to motivate said wheel, the steam motivating said wheel flowing therefrom to said outlet, means to, by-pass steam from said steam chest through said casing to said outlet, heating means in said heater and connected to the outlet of said turbine whereby steam flowing from said outlet passes through said heating means, and air moving means operated by said turbine and circulating air through said heating means to heat said air, said air moving means also expelling the heated air from said unit heater.

4. A unit heater comprising a casing, a shaft journaled in hearings in said casing, fans mounted on said shaft, a heating coil mounted in said casing below said fans, said casing'having an open lower end, a fitting at one end of said casing, a turbine connected to said shaft and including a housing and an outlet, said outlet being mounted on said fitting and said fltting being connected to said heating coil whereby steam from said turbine flows to said heating coil, means for by-passing steam to the outlet of said turbine, the steam operating said turbine also flowing through said outlet, and means regulating the speed of the fans and the heat of the coil.

5. In a device of the class described, a housing having supporting means atone end thereof, a driving member on said supporting means, a shaft extending across said housing and having one end thereof supported by the bearings of said driving member and being rotatable by said driving mem ber, fans on said shaft for drawing air into and for expelling air from said housing, and an adjustable bearing on said housing and adapted to receive the free end of said shai'tand adapted to be adjusted to align said shaft with the shaft of another means for rotating the shaft.

JOSEF Y. DAHLSTRAND. 

